Mask Clearing
There are several reasons why water may trickle inside your mask during a dive. It could be excessive facial hair, a poor fitting mask or maybe you're smiling too much underwater. Clearing water from a partially flooded mask is not difficult for most divers and soon becomes almost automatic after a little practice. If your mask doesn't have a purge valve, clear it by holding the top of the mask firmly against your forehead, then begin exhaling through your nose and look up slightly. The air from your nose forces the water out of the bottom of your mask. With a purge valve, hold the mask firmly against your face and look down. Exhale through your nose and the air forces the water out through the purge valve.

Regulator Clearing
When the regulator is not in your mouth it fills with water which must be cleared before you resume breathing through it. This can be achieved by either using the exhalation method or the purge button method. To clear the regulator using the exhalation method, simply exhale sharply by blowing into the regulator with the second stage in an upright position so that the exhaust valve is the lowest point. If you don't have much air inside your lungs to clear it with, you will be better using the purge method. To do so, place the second stage in your mouth and upright, then block the mouthpiece opening by sticking your tongue against it. This prevents water entering your throat and causing you to cough. Briefly push the purge button and the air from the second stage forces the water out of the exhaust valve allowing the diver to resume breathing normally.

Please Note: This information is meant as a guide for scuba divers and does not replace proper training and a Diving Certification